Orban OPTIMOD 8685, Руководство по эксплуатации

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OPTIMOD SURROUND PROCESSOR INSTALLATION
2-13
E) Set the 2.0 output sample rate to 32, 44.1, 48, 88.2, or 96 kHz.
9. Set surround and 2.0 output levels.
A)
L
OCATE
to the Set Output Levels screen (
S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
8
).
B) Set the
S
URROUND
O
UTPUT
L
EVEL
control to the desired peak level in units of
dB with reference to digital full-scale. (Note: This control is labeled S
URROUND
O
UTPUT
100% in PC Remote.)
–2.0 dBfs is an appropriate value. It provides some headroom for any over-
shoots introduced by equipment (like codecs) following the 8685.
Note that if a given output is fed with a non-limited signal (
AGC
or
LIMIT),
the
peak level will not be controlled tightly.
•
IMPORTANT: In MB L
IMIT
mode, the 8685’s S
URROUND
O
UTPUT
L
EVEL
and
S
URROUND
O
UTPUT
L
EVEL
controls do not adjust loudness; they only set the
maximum peak level at the 8685’s output. This is to reduce the likelihood
of setup errors when the 8685 is driving a Dolby Digital channel. The active
D
IALNORM
value and the MB L
IMITER
D
RIVE
controls set output loudness.
•
Regardless of the output mode, do not try to adjust loudness at the re-
ceiver by using the 8685’s
O
UTPUT
L
EVEL
controls. Use these controls only to
set output headroom. In MB+L
IMIT
mode, use the D
IALNORM
control to set
loudness. In
MB
mode, use the
MB L
IMITER
D
RIVE
control in the active preset.
In AGC and AGC+L
IMIT
modes, use the AGC L
IMITER
D
RIVE
control in the ac-
tive preset.
•
If you have readjusted any L
IMITER
D
RIVE
control (located in the M
ULTIBAND
M
ODIFY
screens for the surround and 2.0 processing), you must save the re-
sult as a user preset in order to avoid the possibility of losing your settings,
which will otherwise happen if you recall a different preset.
This will allow you to use the full amount of headroom available in the
transmission channel following the 8685 and, in digital television service,
will minimize or eliminate the need to apply peak limiting to the signal.
This is because the Dolby Digital system allows you to use the
D
IALNORM
metadata parameter to ensure that there is enough peak headroom
through the transmission system. For most digital television transmis-
sions, setting
D
IALNORM
to –24 dB or below (i.e., closer to –31 dB) will en-
sure that no peak limiting ever occurs, assuming that you set loudness
with the 8685’s
L
IMITER
D
RIVE
control to make the 8685’s Loudness Level
meter peak at 0 dB with typical dialog and set the 8685’s
O
UTPUT
control
to –2.0 dBfs, which allows 2 dB of peak headroom for overshoots in the
AC3 codec.
C) Set the
2.0 O
UTPUT
control to the desired peak level in units of dB with refer-
ence to digital full-scale.
D) Set the
A
NALOG
O
UTPUT
control to the desired peak level in units of dBu,
where 0 dBu = 0.775 v r.m.s.